In normal cerebral development, language function typically becomes lateralized in the left hemisphere. It is theorized that disturbances in the development of this cerebral asymmetry may result in language dysfunction such as dyslexia and dysphasia. Recently, it has been reported that language disturbances occur in many children who were born prematurely and who have suffered insults such as asphyxia and hyperbilirubinemia. Premature infants have also been shown to have abnormal brainstem evoked responses (BSERs) associated with auditory reception. Thus, it is possible that perinatal insults could lead to disturbances in normal central nervous system development which result in later language disabilities. The extent to which such language impairments are related to nervous system development, and to the subsequent limitations placed by neonatal insults upon cognitive capacities, is unknown. Without knowledge of how deviations in the course of normal ontogenesis affect acquisition of higher cognitive functions such as language, remediation can only proceed haphazardly. Indeed, remediation usually begins after a problem such as school failure occurs. By this time emotional difficulties may have seriously complicated the diagnostic situation. The present proposal seeks to provide information concerning the ontogenesis of higher cognitive functioning such as language in high risk and in normal infants. The investigation will focus on physiological measures of brainstem and neocortical functioning, and the relationship of these measures to the acquisition of language-related skills. Specifically, maturation of the brainstem and cortex will be assessed electrophysiologically with the brainstem evoked response (BSER) and the cortical auditory evoked response (AER) respectively. Configurational changes in these responses have been associated with brain maturation. Language acquisition will be determined through use of criterion-referenced performance scales and parental interviews. Studies relating these measures to one another have not been previously reported. Information about the dynamic interrelationship among these measures occurring over the first year of life can provide a better understanding of the effects of early CNS insult on brain maturation and language development, and thus a basis for early detection and remediation.